Britain will resettle up to 20,000 refugees who have fled from the conflict in Syria, Mr Cameron announced on Monday, but some may not arrive until the end of the decade and will face deportation after they’ve been in the UK for five years.

Mr Cameron claimed the UK’s resettlement scheme would ensure that “vulnerable children – including orphans – will be a priority”. But it later emerged all those accepted under the scheme will only be given the right to remain in the UK for five years.

The former leader of the Liberal Democrat Paddy Ashdown said this suggested that orphans and children will be deported at age 18 having made a new life in Britain.

Minister in the Lords just confirmed refugee orphans and children brought in under Cameron’s scheme will be deported at age 18.

As Baroness Stowell of Beeston repeated the Prime Minister’s statement to peers in the chamber, Lord Ashdown challenged her to answer whether any child or orphan brought under the scheme would be deported at the age of 18 as, he said, was the case with existing legislation.

Lady Stowell responded by explaining that there was a clear legal framework applied to people arriving as refugees.

“I’m not suggesting there are a new set of rules or change to existing rules because of this expanded refugee programme at this time,” she said.

In a major U-turn, the Government announced that the UK will accept up to 20,000 refugees by 2020 after The Independent’s petition urging the Government to take action to help those displaced by war garnered over 360,000 signatures. The catalyst was a in

Mr Cameron told the House of Commons on Monday that the refugee crisis is the “biggest challenge” facing Europe, and that the UK must carry out its “moral responsibility” to help those affected.

“Given the scale of the crisis and the suffering of the Syrian people it is right that we should do much more,” he said.

“In doing so, we will continue to show the world that this country is a country of extraordinary compassion, always standing up for our values and helping those in need,” he went on.

However, Mr Ashdown’s claim appears to expose the sting in the tail of the Government’s plans, which were immediately met with shock on Twitter. Mr Ashdown’s post was quickly shared over 3,000 times in the space of two hours.